Role of tumour necrosis factor-a in the regulation of T-type calcium channel current in HL-1 cells.
Clin Exp Pharmacol Physiol
; 43(7): 706-11, 2016 07.
Article
em En
| MEDLINE
| ID: mdl-27119319
ABSTRACT
Increasing evidence indicates that inflammation contributes to the initiation and perpetuation of atrial fibrillation (AF). Although tumour necrosis factor (TNF)-α levels are increased in patients with AF, the role of TNF-α in the pathogenesis of AF remains unclear. Besides L-type Ca(2+) currents (IC a,L ), T-type Ca(2+) currents (IC a,T ) also plays an important role in the pathogenesis of AF. This study was designed to use the whole-cell voltage-clamp technique and biochemical assays to explore if TNF-α is involved in the pathogenesis of AF through regulating IC a,T in atrial myocytes. It was found that compared with sinus rhythm (SR) controls, T-type calcium channel (TCC) subunit mRNA levels were decreased, while TNF-α expression levels were increased, in human atrial tissue from patients with AF. In murine atrial myocyte HL-1 cells, after culturing for 24 h, 12.5, 25 and 50 ng/mL TNF-α significantly reduced the protein expression levels of the TCC α1G subunit in a concentration-dependent manner. The peak current was reduced by the application of 12.5 or 25 ng/mL TNF-α in a concentration-dependent manner (from -15.08 ± 1.11 pA/pF in controls to -11.89 ± 0.83 pA/pF and -8.54 ± 1.55 pA/pF in 12.5 or 25 ng/mL TNF-α group respectively). TNF-α application also inhibited voltage-dependent inactivation of IC a,T, shifted the inactivation curve to the left. These results suggest that TNF-α is involved in the pathogenesis of AF, probably via decreasing IC a,T current density in atrium-derived myocytes through impaired channel function and down-regulation of channel protein expression. This pathway thus represents a potential pathogenic mechanism in AF.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator de Necrose Tumoral alfa
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Canais de Cálcio Tipo T
Limite:
Animals
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Clin Exp Pharmacol Physiol
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
China